Positive displacement porting systems on gerotor oil pumps generally consist of an intake port, an exhaust and an internal relief system which directs relief oil from the exhaust port back into the intake port.
There have been various designs heretofore in oil pumps including gerotors oil pumps in order to efficiently pump fluids.
For example, U.S. Pat. No. 3,289,599 relates to a gear pump.
More particularly, U.S. Pat. No. 3,995,978 teaches inlet ports which are generally arcuate or kidney shaped which extend circumferentially for approximately the line of eccentricity on one side of the hydraulic device to approximately the line of eccentricity on the opposite side of the hydraulic device.
Moreover, U.S. Pat. No. 4,492,539 illustrates a gerotor pump having displacement control means for changing the volume of fluid delivered.
Yet another arrangement illustrated in U.S. Pat. No. 4,767,296 which shows that when the in rotor rotates, a sealed space has its volume reduced to have internal oil pressure accumulated.
Finally, U.S. Pat. No. 4,758,130 discloses various arrangement of ports or galleries of a pump.
These an other arrangements of hydraulic pumps and in particular porting systems have generally limited utility.
It is an object of this invention to provide a more efficient porting system for hydraulic devices and in particular to provide a more efficient porting system for gerotor oil pumps.
It is an aspect of this invention to provide a porting system for a hydraulic device comprising; a housing having a chamber communicating with an intake port and an exhaust port; a pair of rotary gears disposed internally of said chamber adjacent said ports and defining expanding and contracting pockets as said gears rotate over said intake port and said exhaust port respectively; wherein said ports have a cross-sectional area in the direction of rotation which varies with the angular displacement of said gears whereby the incremental rate of change of said cross-sectional area is based on said rate of change of said expanding and contracting pockets.
It is another aspect of this invention to provide a hydraulic pump for pump fluids comprising; a housing having an intake passage for introducing said fluid, exhaust passage for exhausting said fluid and an end face, said intake and exhaust passage defining at said end face and intake port for receiving said fluid and said exhaust port for exhausting said fluid; an internally tooth rotor having an axis of rotation and an externally tooth rotor eccentrically disposed within said internally tooth rotor and having an axis of rotation, said axis of rotation being spaced apart; a shaft operatively connected to one of said rotors; said teeth of said rotors inter engageable to define a plurality of expanding and contracting volumes as said rotors rotate about said intake port and said exhaust port respectively; said ports having a cross-sectional area in said axial direction which changes with the angular displacement of said rotor, whereby the increment rate of change of the cross-sectional area along the entire port is inversely proportional to the incremental rate of change of expanding and contracting volumes respectively.
It is a further aspect of this invention to provide a method of maintaining a substantially constant acceleration of fluid within the entire area of an intake port and an exhaust port defined by an intake passage and an exhaust passage communicating with a chamber having rotary gears defining expanding and contracting pockets as said gears rotate within said chamber by utilizing ports having a cross-sectional area in the direction perpendicular to said rotation of said gears which with the angular displacement of the rotary gear whereby the incremental rate of change of the cross-sectional area is inversely proportional to the rate of change of change of said expanding and contracting pockets.
It is yet another aspect of this invention to provide a method of producing an intake port and exhaust port in a hydraulic device having a fluid chamber with rotary gears disposed within said fluid chamber adjacent said port so as to define expanding and contracting pockets as said rotary gears rotate about an access within said fluid chamber, said method comprising the steps of:
(a) determining the radial and axial size of said ports; PA0 (b) determining the initial and final depth or said ports; PA0 (c) determining the rate of change of said pockets as said rotary gears rotate about said ports; PA0 (d) manufacuture the depth of said ports wherein the cross-sectional area of said passages varies in relation to the rate of change of said expanding and contracting pockets.